1. Field Of The Invention
The present invention relates generally to vascular sheaths of the type used to provide communication with a lumen of a blood vessel during various diagnostic or therapeutic medical procedures.
2. Description Of The Prior Art
In 1991, around 3,000,000 punctures of human arteries were performed in the United States alone. These punctures are usually done for diagnostic cardiac or radiological procedures and also for therapeutic procedures. Such procedures include coronary and peripheral angioplasties and insertion of devices such as intra-aortic balloon pumps.
The percutaneous puncture of the artery usually is performed by sticking the artery with a needle through which a guide wire is inserted. Over this guide wire a dilator is advanced into the artery, and a sheath is often mounted onto the dilator. The dilator is then removed and the distal end of the sheath is left inside the lumen of the artery. A small proximal segment of the sheath is left outside of the artery and outside of the skin of the patient. This proximal segment of the sheath usually contains a hemostatic valve to prevent bleeding from the artery through the sheath.
Sheaths currently in use are typically flexible having one thin wall. They are usually removed from the artery immediately after the procedure or within several hours.
In recent years, the practice has developed of treating many patients with anticoagulation medication such a Heparin. The presence of the anticoagulation medication in the patient's system, of course, exacerbates problems of bleeding.
Due to the increased bleeding problems, the arterial sheath is very often left in situ after the invasive procedure. The sheath is left in situ for sufficient time for the effect of the anticoagulation drugs to dissipate so that the problem of bleeding will not be exacerbated upon removal of the sheath. When the sheath is left in situ for long periods of time, there is a high incidence of bleeding to the outside of the artery when blood seeps through the perforation around the sheath. This bleeding can create hematomas and pseudoaneurysms.
The present invention is directed to an improved arterial sheath which is designed to minimize bleeding around the sheath while the sheath is in place through the perforation in the artery.